package code.starivan.leetcode;

/**
 * Created by Ivan on 2015/10/21.
 */

/*
Given a positive integer n, find the least number of perfect square numbers (for example, 1, 4, 9, 16, ...) which sum to n.

        For example, given n = 12, return 3 because 12 = 4 + 4 + 4; given n = 13, return 2 because 13 = 4 + 9.

        Credits:
        Special thanks to @jianchao.li.fighter for adding this problem and creating all test cases.
*/

public class N279_PerfectSquares {

    public static void test(){
        System.out.println(new N279_PerfectSquares().numSquares(12));
    }

    public int numSquares(int n) {
        if(n<=0){
            return 0;
        }

        int[] help=new int[n+1];
        help[1]=1;
        for(int i=2;i<=n;++i){
            int min=Integer.MAX_VALUE;
            for(int j=1;j*j<=i;++j){
                if(j*j==i){
                    min=1;
                    break;
                }else{
                    min=Math.min(min,help[i-j*j]+1);
                }
            }

            help[i]=min;
        }

        return help[n];
    }
}
